Quantitative analysis of a biological sample of unknown quantity

ABSTRACT

Disclosed is a method for testing a modified specimen such as a dried blood spot, plasma or serum specimen, for an analyte of interest, such as cholesterol. In accordance with the disclosed subject matter, the level of the analyte of interest in the medium from which the modified specimen was obtained (e.g., from a patient&#39;s blood) is determined based on the level of an analyte in a solution formed from the modified specimen and on the level of at least one normalizing analyte. The analyte and normalizing analyte each may be an ion, compound, biochemical entity, or property of the specimen. Also disclosed are a fluid collector and a fluid collection device.

RELATED APPLICATION

This application is a continuation-in-part of U.S. patent applicationSer. No. 10/421,086, filed Apr. 23, 2003, which claims priority to priorapplication Ser. No. 60/374,629 filed Apr. 23, 2002. Both priorapplications are hereby incorporated by reference in their entireties.

TECHNICAL FIELD OF THE INVENTION

The invention is in the field of testing, in particular quantitativetesting, and in preferred embodiments medical testing. In highlypreferred embodiments, the invention is directed towards the testing ofbody fluid specimens, in particular blood or serum specimens.

BACKGROUND OF THE INVENTION

Modem medical and wellness practices increasingly make use ofself-administered tests and self-collection of test specimens. Forinstance, U.S. Pat. Nos. 5,978,466; 6,014,438; 6,016,345; and 6,226,378,issued to Richard Quattrocchi and assigned to Home Access HealthCorporation of Hoffman Estates, Illinois, all disclose a method ofanonymously testing for a human malady. In accordance with certainembodiments of the subject matter disclosed in the foregoing patents, apatient obtains a blood specimen, typically by pricking his or herfinger, and allows the blood to wick onto a blood spot card. After thecard has dried, the user then sends the blood spot card to a medicaltesting facility, where it is tested to determine whether the patient isafflicted with a specific malady. The user may contact the facilityanonymously to receive the test result.

The subject matter of the foregoing patents is usable in connection withtesting for the presence of human antibodies directed against viralantigens in the blood, for instance, in determining whether a patient isinfected with HIV (human immuno-deficiency virus) or with a hepatitisvirus. Another document, U.S. Pat. No. 5,435,970, issued to Mamenta etal. and assigned to Environmental Diagnostics, Inc. of Burlington, N.C.,discloses a device for separating blood cells from biological fluids,for instance, for separating serum from whole blood. The devicedisclosed in the '970 patent purports to enable the shipment and testingof a serum sample.

The blood spot and serum specimen cards known in the art are suitablefor use in the collection of specimens for qualitative testing, i.e.,testing for the presence or absence of a given compound in blood or agiven medical condition. Heretofore, however, such blood spot and serumcards have been somewhat unsatisfactory in the quantitative testing ofblood and serum specimens.

For instance, general wellness protocol indicates the measurements of apatient's total cholesterol value, which is the number of milligrams oftotal cholesterol in a deciliter of blood. The value is often used inconjunction with a full lipid profile, which provides levels oftriglycerides, HDL (high density lipoprotein) cholesterol, and LDL (lowdensity lipoprotein) cholesterol in a patient's blood. It can be verydifficult to gauge the amount of blood or serum that is present in theblood or serum spot card. Particularly when the blood or serum spot cardhas been self-prepared by a person without medical training, it isdifficult to know to certainty whether the spot card has been“underfilled” with less than the intended quantity of blood or serum or“overfilled” with more than the intended quantity. If the amount ofblood and serum varies by even a small amount over or under the expectedlevel, the usefulness of the quantitative test can be severelydiminished. For instance, it is generally thought that a person's totalcholesterol number should be under 200 mg/dl, with cholesterol numbersabove 240 mg/dl being considered high and with intermediate cholesterolnumber being deemed borderline. A 10% margin of error in a cholesteroldetermination of 220 mg/dl provides no information as to whether theperson's cholesterol level is low, intermediate, or high.

In recognition of these problems, the prior art has provided attempts toprovide a quantitative determination of analyte levels in a bloodspecimen. For instance, U.S. Pat No. 6,040,135, issued to Steven Tyrelland assigned to Biosafe Laboratories, Inc., Chicago, Ill., purports todisclose a method for correcting for blood volume in a serum analytedetermination. The method that is purportedly disclosed by this documentis limited and is believed generally to be somewhat unsatisfactory.

The invention seeks to improve upon prior art testing methods, and toprovide a method for quantitative testing of modified specimens such asdried blood spot and dried serum specimens.

THE INVENTION

The invention provides multiple embodiments in the field of testing, inparticular medical testing. In accordance with the invention, a modifiedspecimen, preferably a dried blood fluid sample, such as a dried serumor dried whole blood specimen of unknown quantity, is eluted(re-solubilized) and then tested for an analyte. The level of analyte inthe blood from which the modified blood specimen was obtained isdetermined from the level of analyte in a solution formed from the bloodspecimen. A normalizing analyte, which in the preferred embodiment issodium ion, chloride ion, and/or osmolality, is measured and is used inconjunction with the solution level of analyte to determine the level ofanalyte in the blood from which the modified specimen was obtained. Theinvention is not limited to the field of medical testing but, to thecontrary, is useful in connection with other forms of testing. Theinvention further provides methods for preparing a database of testresults, for preparing a regression using a database of test results,and for providing test results to a user.

In alternative embodiments the invention further encompasses a fluidcollector that includes an absorbent substrate coated with a saccharide.A device that includes the collector (as described hereinbelow) also isencompassed by these embodiments.

Other features of preferred embodiments of the invention are set forthhereinbelow.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a flowchart representing steps in a method for calculating thelevel of an analyte in blood from which a blood specimen was obtained.

FIG. 2 is a flowchart representing steps in an alternative method forcalculating the level of an analyte in blood from which a blood specimenwas obtained.

FIG. 3 is a flowchart representing steps in a method for providing testresult information to a user.

FIG. 4 is a representation of a database record correlating test resultinformation with a test number.

FIG. 5 is a flowchart representing steps in a method for preparing adatabase of test results and test numbers.

FIG. 6 is a flowchart representing steps in a method for preparing adatabase of blood analyte levels, solution analyte levels, and solutionnormalizing analyte levels.

FIG. 7 is a representation of a database record for a databasecontaining blood analyte level information, solution analyte levelinformation and solution normalizing analyte level information.

FIG. 8 is a schematic illustration showing various communicationsbetween a customer, a results providing facility, and others inconnection with a testing protocol.

FIG. 9 is a perspective view of the obverse side of a blood collectiondevice useful in conjunction with the invention.

FIG. 10 is a perspective view of the reverse side of the device shown inFIG. 9.

FIG. 11 is a representation of a kit useful in conjunction with theinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The invention is applicable to the testing of any specimen that ismodified from its original form prior to testing. Most commonly, thespecimen is a dried specimen, which has been dried to facilitate storageor transport of the specimen or for other purposes. In preferredembodiments of the invention, the specimen is a medical specimen, and inhighly preferred embodiments of the invention, the specimen is a bloodfluid specimen, by which is contemplated a dried blood spot, a driedserum spot (for instance, as obtained from the device disclosed in U.S.Pat. No. 5,435,970 or that shown in U.S. Pat. No. 4,839,296 issued toKennedy, et al. and assigned to Chem-Elec, Inc. of North Webster, Ind.),or another blood fluid specimen. The invention is applicable to thetesting of the modified specimen for any suitable purpose, and inparticular to testing for any analyte in the specimen. For instance,when the specimen is a blood fluid specimen, the test may be a test forprostate specific antigen (PSA), alanineamino transferase (ALT), lipids,such as triglycerides, high density lipoprotein (HDL), low densitylipoprotein (LDL), or any other analyte of interest. The invention isapplicable to the determination of the level of analyte in the originalspecimen, for instance, the level of total cholesterol in the blood fromwhich a blood fluid specimen has been obtained. The “level” of theanalyte can be expressed in any suitable units, such as molarconcentration, weight concentration, or the like. Blood serum isparticularly preferred, but it is contemplated that other fractions suchas cells, platelets, gamma globulins, plasma or the like may beemployed. For instance, it may be designed to test blood cells inconnection with a fasting plasma glucose test. More generally, any bodyfluid is susceptible to analysis in conjunction with the invention. Inlight of the foregoing, the preferred embodiments of the invention willbe further described with respect to the determination of the lipidprofile in a blood sample, but it should be understood that theinvention is not limited thereto.

The facility or other entity that performs the test of the blood fluidspecimen may or may not be the same entity that calculates the level ofthe analyte in the blood fluid specimen or the entity that receives aninquiry from a user and reports the test results to the user. To testthe blood fluid specimen, the specimen is first received by the testingentity and is eluted with a liquid, preferably deionized water. It iscontemplated that the liquid may be a non-aqueous liquid or may be anaqueous solution, preferably a solution that is free or essentially freeof sodium ions or any other normalizing analyte. Alternatively, thesolution may have a known amount of the normalizing analyte that can betaken into account during normalization. Preferably, when the testingentity is a testing facility that is intended to test numerousspecimens, the eluant is added in a standard amount, which typically is600 μl (0.6 ml). The eluant in some embodiments may be a bufferedelectrolyte solution.

After eluting the specimen, preferably the specimen first is tested forthe content of a normalizing analyte, such as sodium and chloridecontent, and in some embodiments osmolality, which generally representstotal content of sodium, glucose, and blood urea nitrogen (BUN). To testfor sodium and chloride, an ion specific electrode (ISE), such as thatsold by Orion may be employed. Preferably, information concerning boththe sodium and the chloride content of the solution are obtained, theinformation being, for instance, analog information such as anelectrical signal or digital information such as a printout representingthe sodium or chloride content or a digital signal containinginformation concerning the sodium or chloride content. Most preferably,osmolality also is measured. It should be noted that the invention isnot limited to the use of sodium or chloride as normalizing analytes,but to the contrary, any other analyte (which includes a property suchas osmolality) may be measured. It is contemplated in preferredembodiments that the sodium, chloride, and osmolality levels aremeasured against a predetermined range to determine whether the amountof serum is sufficient to perform an adequate test. For instance, it iscontemplated that for a cholesterol test, there ideally should be atleast approximately 15-17 μl of serum available for testing. If thesodium content of the eluted solution demonstrates that the serum levelis far outside this range, the specimen may be rejected as unsuitablefor testing. Generally, the specimen may be rejected if there isinsufficient serum in the solution, although it is contemplated that insome cases excess serum may be grounds for rejection. Persons skilled inthe art may determine how far outside of the desired range the contentof normalizing analyte may be allowed to vary without triggeringrejection of the specimen.

Before or after the levels of the normalizing analytes are determined(but preferably after), the solution can be split into four aliquots, or“channels.” Each channel is then respectively tested for triglyceridelevel, HDL level, LDL level, and in a preferred embodiment, ALT level(which may be of interest in informing a physician whether the patienthas an abnormal liver which would contraindicate the use of certaindrugs). The analyte levels are measured using any technique known in theart or otherwise found to be suitable. For instance, a cholesterol testis disclosed in Allain, C. C., Poon, L. S., Chan, G. S. G., Richmond,W., and Fu, P. C., Clin. Chem. 20:474-75 (1974); see also Roeschlau, P.Brent, E. and Gruber, W A., Clin. Chem. Clin. Biochem. 12:226 (1974). Atest for HDL is disclosed in RiFai, N., Warnick, G. R., Ed., LaboratoryMeasurement of Lipids, Lipoproteins, and Apolioproteins (1994). A testfor triglycerides is disclosed in McGowan, M. W., Artiss, J. D.,Strandbergh, D. R., Zak, B. Clin. Chem. 29:583 (1983). A test for theliver enzyme ALT is disclosed in Wroblewski, F., LaDue, J. S., Proc.Sec. Exp. Biol. Med. 34:381 (1956). The invention is not limited to theforegoing tests or analytes, but to the contrary is applicable to othertests for these or other analytes.

After the analyte levels have been measured, the level of at least oneanalyte (and preferably all analytes) in the blood from which the bloodfluid specimen was obtained is calculated or otherwise determined basedon the solution level of the analyte and on the solution level of atleast one normalizing analyte. It is contemplated that the calculationof a blood analyte level may be as simple as multiplying the solutionanalyte level by the ratio of the blood normalizing analyte level to thesolution normalizing analyte level, the blood normalizing analyte levelbeing estimated based on the mean of a normal population distribution.For instance, it is believed that the normal blood sodium level inhumans ranges from 136 to 142 mEq/L with a mean of 139 mEq/L and thenormal chloride level ranges from 95 to 103 mEq/L with a mean of 99mEq/L. It is contemplated that through the use of two normalizinganalytes, the blood analyte level may be determined by calculating theblood analyte level based on the first normalizing analyte level,calculating the blood analyte level based on the second normalizinganalyte level, and then calculating the mean average of the bloodanalyte levels thus determined.

If additional normalizing analytes are evaluated, the mean average ofall blood level analytes thus determined may be calculated; if desired,where there are at least two normalizing analytes, the average may beweighted towards a specific normalizing analyte. For instance, it iscontemplated that Bayesian statistical methods may be used to assign arelative weight to the blood analyte levels determined with reference toeach analyte. Such statistical techniques may take into account not onlythe absolute magnitude of the level of the normalizing analyte level butalso the difference between the actual level and the magnitude expectedbased on the expected amount of serum, and the standard deviation of thenormal population distribution of the analyte. These techniques,sometimes referred to as “maximum likelihood” or “prior probabilityanalysis” techniques, may be used to provide an approximation of theblood analyte level. Further testing concerning such statisticaltechniques may be found in Casella, G., Berger, R. L., StatisticalInference (1990) and Carlin, B. P., Louis, T. A., Bayes and EmpiricalBayes Methods for Data Analysis (2d Ed. 2000).

Further details concerning the distribution of sodium, chloride, andosmolality in the normal human population may be found in Ravel,Clinical Laboratory Medicine (6th Ed. 1995); see also Penney, M. D. andWalters, G., Ann. Clin. Biochem. 24:566-71 (1987) and Fraser, C. G.,Cummings, S. T. Wilkinsen, S. O. et al., Clin Chem. 35:783-86 (1985). Itis further contemplated that a more complicated function of solutionanalyte level and the levels of one or more normalizing analytes may beemployed to calculate the blood analyte levels.

With reference now to FIG. 1, the generalized method shown therein isapplicable where the same entity performs the test and calculates theblood analyte level. Thus in steps 101 and 102 respectively the ISE(e.g., sodium) is immersed into the solution, and sodium levelinformation is obtained. The steps are repeated for the receipt ofchloride information, as shown in steps 103 and 104. Informationconcerning the analyte of interest is received in step 105, and theblood analyte level is calculated in step 106. If, in step 107, it isdesired to test an additional analyte for the same specimen, controlpasses to step 105 where the solution analyte information is receivedfor the new analyte. It is contemplated that the steps of testing forthe analytes of interest and the normalizing analytes may be performedby one entity and that the calculation of the blood analyte level may beperformed by a separate entity. Thus, for instance, in FIG. 1, steps 101and 103 may be omitted if the entity calculating the blood analyte levelis not the same entity as the entity that performs the test. The methodoutlined in FIG. 1 is very general, and other steps may be added, stepsmay be omitted or performed in a different order, and more generally themethod may be otherwise performed. For instance, steps of elution andverifying proper serum level are not shown, but are preferably employed.

It is contemplated that the analyte level, first normalizing analytelevel, and second normalizing analyte level may be independentlydetermined and these values used to calculate the blood level of theanalyte. For instance, the cholesterol tests hereinbefore discussedtypically are performed via enzymatic techniques in which the opticaldensity of a solution is measured. The “cholesterol value” of thesolution then may be expressed as:CV _(s) =f(OD)wherein CVs, the solution cholesterol concentration, is calculated as afunction of the optical density, OD, when analytical reagents are addedto the sample in accordance with testing techniques known or otherwisefound to be suitable. The solution sodium concentration, or Na_(s), maybe used to calculate the blood cholesterol level, CV_(b), in thefollowing manner:CV _(b) =f(CV _(s) , Na _(s))Numerous other forms of such calculations are possible. For instance, acorrection factor (CF) may be determined as a function of the solution'ssodium level, wherein:CV _(b) =f(CV _(s) , CF)andCF=f(Na _(s))

It is alternatively contemplated that a single apparatus or system maybe designed for the calculation of blood analyte levels, wherein ananalog or digital electrical signal is generated corresponding to thelevels of analyte and normalizing analyte in the solution. For instance,the blood cholesterol number may be calculated as a function of themagnitude of two electrical signals:CV _(b) =f(E ₁ , E ₂)wherein E₁ represents the magnitude of an electrical signal receivedfrom a spectrophotometer in measuring optical density for purposes ofevaluating total solution cholesterol level and E₂ represents themagnitude of an electrical signal received from an electrode specific tosodium.

In actual practice, it is contemplated that numerous variables willaffect the results obtained for a given set of specimens. For instance,the readings obtained from an ISE may “wander” from day to day, and thedevice used to collect the blood or other fluid specimen may containimpurities (such as sodium) that have the potential to introduce errorsinto the test. For this reason, from time to time a “tare” procedure maybe employed. Periodically, a plurality of specimens having a known ormeasurable analyte level is provided, and from these specimens areprepared modified specimens, the modified specimens being specimens asmodified in the manner expected of the unknown specimens. For instance,some number (e.g., six) blood specimens may be periodically placed ontoa blood spot collection device similar to those used in the field anddried, followed by elution of the dried samples to form solutions. Thesolutions are then tested for the level of the analyte and one or morenormalizing analytes. From these tests, an algorithm for determining theoriginal fluid analyte level as a function of the measured analyte leveland the levels of the normalizing analyte or analytes may be derived.Using this algorithm, modified fluid specimens may be analyzed, whereinthe levels of analyte and normalizing analyte may be measured, and thelevel of analyte in the original specimen may be determined as afunction thereof. Errors introduced by impurities (such as sodium) inthe collection device will be resolved by this methodology, and errorsintroduced by factors such as machine calibration will be resolvablewith periodic re-calculation of the algorithm. The tare procedure may beperformed occasionally or regularly at predetermined intervals (e.g.,every day, week, month, or year).

The foregoing exemplary equations are not meant to be exhaustive but, tothe contrary, are intended to illustrate that innumerable variants ofthe methods for calculating the blood analyte level are included withinthe scope of the invention. For instance, with respect to FIG. 2, in onesuch variant, an ISE (sodium) is immersed into an eluted sample at step201, and a signal corresponding to the sodium level is received at step201. The signal may be a digital signal, or may be an analog signal, thelevel of which is recorded. At steps 203 and 204, the same steps arerepeated for chloride level, and at steps 205 and 206 respectively, atest for the analyte is performed and a signal is received correspondingto the analyte level. At step 207, the solution sodium level iscalculated; at step 208, the chloride level is calculated, and at step209, the solution analyte level is calculated. At step 210, the bloodanalyte level is calculated, in this instance based on the magnitude ofthe solution sodium level, the solution chloride level, and the solutionanalyte level. If, at step 211, it is desired to test for an additionalanalyte for the same specimen, control passes to step 205. In such case,if the solution sodium and chloride level have been stored, steps 207and 208 may be omitted after a signal is received corresponding to thesecond analyte level. The process may be controlled by any suitablemicroprocessor or microcontroller (not shown).

As stated hereinabove, it is contemplated that the entity who providestest results to a user, who may or may not be the health careprofessional who has ordered the test, in turn may be the same ordifferent entity from the entity which performs the calculation of theblood analyte level, which in turn may be the same or different entityfrom the entity which tests the specimen and generates informationcorresponding to the analyte level or levels and the normalizing analytelevel or levels. A very general protocol for a results providingfacility is set forth in FIG. 3, wherein an inquiry is received from auser at step 301, and the user is prompted for his or her test number atstep 302. At step 303, the test number is received, and at step 304, atest result database is queried for test result information. Theinformation is received at step 305 and is provided to the user at step306.

With further reference to FIG. 4, the test result database describedabove may be structured in any suitable manner. With respect to, forinstance, database record 400, the test result information 401, which inthe illustrated embodiment includes two items of information, bloodanalyte information 1 and blood analyte information 2, is correlatedwith the test number 402. The test number may be an anonymous testnumber or may be a test number that is associated with a user, forinstance, elsewhere in the database record 400 (not shown) or in adifferent database.

With reference to FIG. 5, the database may be prepared by creating adatabase record (shown in step 501), receiving test result informationand a test number (shown in steps 502 and 503 respectively) and, asshown in step 504, entering the test number and test result informationinto the database record. More information concerning the role of aresults providing facility in a medical or wellness testing protocol canbe found in the aforementioned Quattrocchi patents and in copendingapplication Ser. No. 09/709,884.

The invention additionally contemplates a method for preparing adatabase for use in calculating blood analyte levels. The blood analytelevel may be calculated with specific reference to the database, oralternatively the database may be used in conjunction with thepreparation of an algorithm for enabling blood level calculation. Thedatabase preferably is prepared with reference to blood having a knownlevel of cholesterol or other analyte of interest. Plural specimens ofblood having different levels of the analyte are then reduced to anmodified specimen, such as a blood spot or serum specimen, and eachspecimen is analyzed for the analyte of interest and for a normalizinganalyte. For instance, with respect to FIG. 6, a database record iscreated at step 601, and known blood analyte level information isreceived at step 602. Information as to the solution analyte level andthe level of two normalizing analytes, sodium and chloride, for example,are received at steps 603-605, and at step 606, the information receivedis entered into the database record. If, at step 607, an additionaldatabase record is to be created, control passes to step 601, wherein anew database record is created for the new specimen. It should be notedthat the order of the steps is not critical, and indeed the database maybe prepared sequentially with respect to each blood specimen (i.e., eachspecimen is reduced to an modified specimen, tested, and the resultsentered into a database record prior to altering the next specimen ofblood), sequentially with respect to database record (wherein all of theblood specimens are reduced to modified specimens prior to entering thefirst database records) or by any other suitable methodology. A databaserecord 700 as shown in FIG. 7 is thus prepared, with entries 701 through704 representing respectively blood analyte level, solution analyte,solution sodium level, and solution chloride level.

As discussed above, rather than being calculated, the blood analytelevel in a blood fluid specimen may be determined with reference to thedatabase, for instance, by finding the solution analyte level andsolution normalizing analyte level or levels in the database that areclosest to those of the specimen. Alternatively, any suitablestatistical or mathematical technique may be used to derive an algorithmfor calculating the blood analyte level from the solution analyte leveland at least one normalizing analyte level. In some embodiments, thealgorithm is first order with respect at least to the solution analytelevel, and may be first order with respect to the solution analyte leveland one or both normalizing analyte levels.

The invention preferably is conducted in accordance with the generalschematic set forth in FIG. 8. Generally the customer 801 purchases atest kit from a physician or retail store 802 (transfer of the kit isshown via transfer communication 805) or in other embodiments a patientis provided with a test kit by or at the direction of a health careprovider. The test kit (not shown in FIG. 8) preferably includesinstrumentalities for allowing the customer to obtain a blood, serum orserum spot specimen. For instance, as discussed more fully in theaforementioned Quattrocchi patents, the test kit may include a lancetfor pricking the user's finger, a blood spot card, or serum spot card,(or the device shown in FIGS. 9 and 10 hereinafter discussed) aninformed consent form, and a test number. After preparing the blood,serum or serum spot card, the customer sends the dried blood specimen toa results providing facility 803 as shown via transfer communication806. In the illustrated embodiment, the results providing facility 803sends the specimen to a separate testing facility 804, as shown viatransfer communication 809. As shown via communication 810, the testingfacility provides the test results to the results providing facility.The results may be “raw” results, i.e., results in which the level ofthe analyte in the blood has not been determined or obtained, oralternatively the testing facility may calculate the blood analyte leveland report that result to the results providing facility. As shown atcommunication 807, the customer contacts the results providing facility,and at communication 808, the results providing facility provides thetest results to the customer. Optionally, the results providing facilitymay be equipped to communicate directly with the physician's office, asshown at communications 811 and 812. Except where transfer of a physicalspecimen is required, the communication may be made via any means ormethod now known or hereinafter discovered, for instance, via telephone,wireless communication, electronic mail or “chat” or other electroniccommunication, or other form of communication.

With reference now to FIGS. 9 and 10, the illustrated fluid collectiondevice 900 includes two gangs 901, 901, each comprising a fluidcollector 903, 904 that is disposed between a superstrate sheet 905 anda substrate sheet 906 and that is generally fixed with respect to thesuperstrate sheet 905. The fluid collector is ordinarily connected tothe substrate sheet 906 (a portion of which is visible) at one end 907,908, although the collector may be flexible and thus not entirely fixedwith respect to the substrate sheet 905. The substrate is provided withat least one aperture (two shown as 909, 910) by which a user mayfluidically transfer blood to the collector. In the illustratedembodiments, secondary apertures 911, 912 are provided. To use thedevice, a user dispenses blood onto the collector, whereby some or allof the blood wicks in the direction shown by arrow 913 until theportions 914, 915 of the collectors 903, 904 visible through thesecondary apertures 914, 915 become tinted, whereupon the user isprovided with an indication that sufficient blood has been collected. Asillustrated, the device preferably is disposed horizontally relative tothe ground during the wicking of blood. Any other suitable indicatorthat an amount of blood predetermined to be adequate may be provided. Inthe illustrated embodiments, instructions 917 are provided on thesubstrate sheet 905 and identification information spaces 918 (shown inFIG. 10) are provided on the substrate sheet 906. The device may beprovided with non-textual machine-readable indicia (such as barcode 919)or textual indicia that indicates, for instance, a test number, codenumber, lot number, or other desired information.

With reference to FIG. 11, the illustrated kit 1100 includes thespecimen collection device 900 illustrated in FIG. 9, and numerous othercomponents, some or none or all of which in practice may be included ina kit. The kit includes a barrier pouch 1103, a dessicant pouch 1104, alancet 1102, and instruction sheet separate from the kit, a results formfrom a previous test, and a requisition form as specifically shown inthe figure. In preferred embodiments, the kit includes a mailing device,most preferably a preaddressed envelope with postage prepaid for sendingthe collection device to a testing facility or other appropriatefacility. In practice, the kit may further include a bandage, gauze pad,and alcohol pad for use with drawing blood from the patient (not shown)and a form for providing informal consent, which informed consent may beprovided anonymously as described in the heretofore mentionedQuattrocchi patents. The barrier pouch should be a pouch that iseffective in protecting the dried blood sample during shipping. Onesuitable barrier material is sold by Caltex Plastics of Vernon, Calif.and comprises a multi-layer barrier film consisting of 25 bleach MGPaper, 48 GA polyester film, 0.0005 aluminum foil, and 0.003 EVAco-polymer, the layers being adhesively bonded together. The pouchpreferably is formed with at least one self-sealing device, such as a“zipper” disposed at at least one end of the pouch. A pouch thatincludes two self-sealing devices, one at each end of the pouch,alternatively may be provided.

The dessicant pouch should be a porous container that includes suitabledessicant effective to provide a dessicating protective effect on ablood fluid specimen, and to some extent to protect the integrity of thecollection device during transport to the physician or patient. Anysuitable dessicant material may be used in conjunction with theinvention. One suitable dessicant is made by SudChemie of Balen, N. Mex.under part number 4286. This material comprises silica and clay disposedin admixture in a 5 gram pouch. Any other suitable dessicant may be usedin conjunction with the invention.

Likewise, any suitable lancet may be employed in conjunction with theinvention. The illustrated lancet 1102 preferably comprises ablood-obtaining lancet such as that presently available from Palco Labsof Santa Cruz, Calif. as the EZ-LETS II. This device includes asingle-use lancet that is spring-loaded to enable the lancet to sharplypierce a user's skin. Any other suitable lancet may be used inconjunction with the invention. The barrier film pouch is sized toreceive the fluid collection device. Preferably, the pouch is sized toreceive the dessicant pouch and the fluid collection device.

An instruction set may be included as a separate sheet within the kit,or alternatively the instructions may be integral with (for example,imprinted on) the fluid collection device. The kit may further includeresults from a previous test. Such is useful, for example, in the caseof patients who require periodic testing, for instance, of bloodcholesterol. The invention encompasses in some embodiments a method ofproviding a test kit and test results to a health care provider and/or apatient, the test results being results from a previous test and thetest kit being a kit as heretofore described. In some embodiments, thepatient responds to an indication in the results form as to whether orwhen to obtain a subsequent blood sample or other type of sample.

The invention contemplates methods wherein a physician is provided witha test kit as heretofore described and wherein the patient's blood isdrawn at the direction of the physician or other health care provider,either at the premises of the health care provider or elsewhere withoutthe healthcare provider being present. In keeping with theseembodiments, the kit may include a requisition form, the requisitionform permitting indication of the type of test or tests to be conductedon the fluid to be collected by the device. In some embodiments, therequisition form lists a plurality of test types, and the healthcareprovider need only indicate (such as with a check mark) the type of testdesired. On any such form, space may be indicated for the health careprovider to indicate any other sort of test desired to be conducted.

In a highly preferred embodiment of the invention, the fluid collectoris an absorbent paper or glass fiber substrate that is coated with asaccharide, preferably a mono or di-saccharide and most preferablyxylose. The saccharide should be present in contact with the substratein an amount effective to inhibit triglycerides ordinarily present inthe expected blood sample from binding to the fiber matrix. Thesubstrate should be one that permits at least substantial separation ofthe red blood cell component of blood cells from other portions of theblood (i.e., serum). It is believed that the saccharide componentpermits more effective recovery of the serum components from thesubstrate sheet. The substrate may be coated only at the surface on oneor both sides with the saccharide, but preferably the substrate iscoated on internal surfaces as well as on the exterior surface. In oneembodiment, 180 μl of a 5% solution of xylose is applied to the internalsurface of the 0.8×7 cm substrate (such that substantially all of thesubstrate is wetted) and allowed to air dry. If the fluid collector isused in the device shown in FIGS. 9 and 10, the blood cells will remainnear the end of the collection device (opposite the direction of arrow913) while the serum will wick toward the other end of the card. Uponreceipt by a testing laboratory, a portion of the fluid collector may beexcised and eluted. Preferably, the excised portion includes a portionof the collector “above” the terminal wicking point of the serum. Onecommercial product (Whatman GF/AVA paper) contains sodium, and it isbelieved that by excising filter paper above the terminal wicking pointa consistent amount of sodium will be introduced into the eluted fluid.The device may be prepared by applying a solution of the saccharide tothe substrate.

The glass fiber paper heretofore described comprises a mat of glassfibers that are at least substantially coated with polyvinyl alcohol.The fibers define a plurality of pores that have a pore size that, inpreferred embodiments of the invention, is effective to at leastsubstantially prevent lysing of red blood cells while permitting atleast substantial separation of serum from red blood cells viadifferential wicking. Any suitable substrate that provides such a poresize and that permits such substantial separation in the absence ofblood cell lysing may be used in conjunction with the invention.Preferably, the average pore size defines a fluid removal rating, asthis term is used in conjunction with filtration technology, of 1.7micron.

The invention enables venous blood analyte levels to be determined fromcapillary blood specimens. It is contemplated that in most embodimentsthe solution analyte level will be normalized to the venous blood levelof the analyte, but it is also contemplated that the solution value maybe normalized to capillary blood level (or for that matter a differentblood level).

The databases discussed herein may be created and stored as computerfiles on a computer readable medium, such as a diskette, hard disk,CD-ROM, DVD-ROM, ROM chip or EPROM chip, or any other suitable medium asmay be now known or hereinafter discovered. The tests for the analyteand normalizing analytes may be performed by any conventional orotherwise suitable technique now or hereinafter found to be suitable,and likewise the analyte and normalizing analyte (which may be discreteatoms, ions, compounds, biochemical materials, or properties) may bethose specifically described herein or others as may be found suitablefor use in conjunction with the invention.

The following examples are provided to illustrate the invention, butshould not be construed as limiting the invention in scope unlessotherwise indicated. Unless otherwise indicated in these examples, themeasured analyte level was corrected using sodium as the solenormalizing analyte. The correction was made using a simple linearregression. It should be understood that more complex single variableand multivariate regressions may be used in conjunction with theinvention, and thus the statistical techniques employed in theseexamples should be viewed as non-limiting. EXAMPLE 1

This example demonstrates the performance of the invention in themeasurement of total cholesterol.

Fifteen patients were used to obtain blood specimens (micro-serumspecimens) via venal puncture. Serum from each specimen was spotted anddried on filter paper with applied volumes ranging from approximately 8to 16 μl. The number of spots for each blood specimen is listed in thecolumn “No.” in the table below. Each spot was eluted and measured forcholesterol and sodium. For each specimen for each patient, thenormalized cholesterol level was calculated based on the level of ameasured analyte in the fluid (cholesterol) and a normalizing analyte(sodium). The normalized cholesterol level was obtained according to thepresent invention using linear regression techniques to yield thefollowing function: Normalized Cholesterol=MeasuredCholesterol/((−0.003306)+0.9781×(Measured Sodium/13)), where 139 (mEq/L)is the population mean for sodium. The regression was calculated basedon five direct measurements of the cholesterol level from the same bloodsample, as listed in the column “Mean Serum Cholesterol.” The meanaverage of the normalized cholesterol values for each patient is givenin the column “mean normalized cholesterol” and the coefficient ofvariation of the normalized cholesterol levels obtained for each patientis listed in the column designated “Normalized Cholesterol CV %.” MeanNormalize Mean Serum Normalized Cholesterol Patient No. CholesterolCholesterol CV % A 11 152.35 153.68 3.85 Ja 12 165.79 162.50 1.42 Il 14180.93 180.47 4.61 Ca 12 186.20 182.28 0.70 Br 10 187.06 185.35 2.93 Mi12 187.14 186.21 1.85 Gr 12 187.42 189.14 1.65 Ed 12 200.38 197.18 1.36Tr 11 220.83 221.89 2.00 Bb 11 232.65 233.06 1.89 Ma 11 236.73 245.531.02 Jo 11 237.37 237.24 1.95 JJ 14 262.41 259.24 1.75 Kt 12 264.30268.23 1.86 TT 13 269.36 273.53 2.79

A comparative linear regression was generated for the data pointscollected in this Example. The linear fit followed the followingequation:Mean Normalized Cholesterol=−7.97 +1.04×Mean Serum Cholesterol,with the correlation coefficient, expressed as R², being greater than0.99.

EXAMPLE 2

This example demonstrates the performance of the invention in themeasurement of HDL.

The same dried spots from the same fifteen patients in Example 1 wereused to obtain a measured value for HDL. The normalized HDL level wasobtained according to the present invention using linear regressiontechniques yielding the following function:

Normalized HDL=HDL/(0.0158+1.060×(Sodium/139)). The following data wasmeasured or calculated in the same manner as in Example 1. Mean SerumMean Normalized Normalized Patient No. HDL HDL HDL CV % II 14 45.7747.03 2.35 A 11 46.05 47.77 2.17 Jo 11 47.40 48.50 2.12 Ja 12 48.8753.22 2.23 JJ 14 49.07 48.15 1.68 Gr 12 49.64 52.45 1.62 Mi 12 59.9658.95 1.69 Br 10 57.20 55.83 2.66 Ed 12 71.00 71.09 0.92 Kt 12 73.0872.46 1.53 TT 13 76.16 75.77 2.27 Ca 12 78.01 75.93 1.50 Bb 11 78.7773.35 1.99 Ma 11 87.84 84.75 0.94 Tr 11 91.15 86.42 1.46

A comparative linear regression was generated for the data pointscollected in this Example. The linear fit followed the followingequation:Mean Normalized HDL=8.15+0.87×Mean Serum HDL,with the correlation coefficient, expressed as R², being greater than0.99.

EXAMPLE 3

This example demonstrates the performance of the invention in themeasurement of triglycerides (TG).

The same dried spots from the same fifteen patients in Example 1 wereused to obtain a measured value for TG. The normalized TG level wasobtained according to the present invention using linear regressiontechniques yielding the following function:

Normalized TG=TG/((−0.0136)+0.9307×(Sodium/139)). The following data wasmeasured or calculated in the same manner as in Example 1. MeanNormalized Normalized Patient No. Mean Serum TG TG TG CV % Ca 12 37.6338.76 1.95 Bb 11 46.86 48.55 1.75 A 11 48.75 50.16 2.73 Ja 12 49.6849.94 3.31 Kt 12 52.15 48.19 1.32 Br 10 55.00 56.56 4.14 Ma 11 56.0556.40 2.03 II 14 59.09 60.88 6.22 Ed 12 62.91 61.65 1.25 Tr 11 66.6967.66 1.63 TT 13 68.76 72.14 13.37 Mi 12 71.84 72.63 1.62 Jo 11 109.28107.10 2.27 JJ 14 117.31 112.24 5.03 Gr 12 139.47 136.74 2.13

A comparative linear regression was generated for the data pointscollected in this Example. The linear fit followed the followingequation:Mean Normalized TG=3.36+0.95×Mean Serum TG,with the coefficient, expressed as R², being greater than 0.995.

EXAMPLE 4

This example demonstrates the performance of the invention in themeasurement of LDL. The same observations from the same fifteen patientsin Example 1, 2 and 3 were used to calculate a value for LDL in serumand a value for LDL in MSS according to the Friedewald formula:Mean Serum LDL=Mean Serum Cholesterol−Mean Serum HDL−Mean Serum TG/5Mean Normalized LDL=Mean Normalized Cholesterol−Mean Normalized HDL−MeanNormalized TG/5, respectively.

The following data was calculated (mean serum LDL was calculated fromthe mean values reported in Examples 1-3) Mean Serum Mean NormalizedNormalized Patient No. LDL LDL LDL CV % A 11 96.55 95.30 5.36 Ca 12100.66 98.82 1.17 Ja 12 106.98 99.22 2.32 Gr 12 109.88 109.00 2.19 Mi 12115.81 112.90 2.80 Tr 11 116.35 121.21 3.11 Ed 12 116.80 113.76 1.98 Br10 118.86 118.21 3.23 Il 14 123.34 119.75 5.72 Ma 11 137.68 149.45 1.72Bb 11 144.51 150.01 2.12 Jo 11 168.11 167.55 2.66 Tt 13 179.45 183.333.33 Kt 12 180.78 186.13 2.19 JJ 14 189.88 189.54 1.89

A comparative linear regression was generated for the data pointscollected in this Example. The linear fit followed the followingequation:Mean Normalized LDL=−8.16+1.07 ×Mean Serum LDL,with the correlation, expressed as R², being equal to 0.98.

EXAMPLE 5

This example demonstrates the performance of the invention in themeasurement of total cholesterol.

One hundred thirty-two patients were used to obtain blood via venalpuncture (venous blood specimens) and by pricking their fingers(capillary blood specimens). Capillary blood was spotted onxylose-coated Whatman GF/AVA filter paper, using a device similar tothat shown in FIG. 9. Capillary blood specimens were dried and theportion of the filter paper which contained separated serum was cut outand eluted. Eluate from each specimen was measured for cholesterol andsodium. The normalized cholesterol level was obtained according to thepresent invention using a variable formula: NormalizedCholesterol=Measured Cholesterol/(A+B×(Measured Sodium/139)). In thisequation, A and B were scalar values that were periodically recalculatedbased on the “tare” procedure heretofore described, whereby a regressionfor six patients was calculated and the A and B values from thisregression were used to calculate normalized cholesterol values forspecimens analyzed before the next tare period. Actual (directlymeasured in venous blood) and calculated normalized cholesterol valvesfor these patients are given below. Patient Serum Cholesterol NormalizedCholesterol 1 172.68 157.54 2 149.25 154.61 3 176.81 175.60 4 189.78187.41 5 170.38 173.03 6 189.67 188.80 7 130.52 128.80 8 266.76 276.31 9151.29 152.49 10 219.86 211.23 11 242.00 251.07 12 232.41 230.66 13173.09 176.48 14 190.89 190.86 15 264.47 260.46 16 236.18 244.49 17272.58 279.76 18 240.29 228.83 19 169.32 166.57 20 192.02 195.03 21239.83 235.33 22 225.13 225.13 23 169.40 156.05 24 197.93 183.67 25151.59 146.26 26 235.43 247.88 27 178.84 170.79 28 196.40 191.34 29240.99 230.52 30 171.53 173.95 31 229.43 229.43 32 217.54 223.84 33187.23 183.58 34 175.68 173.95 35 174.69 172.34 36 251.23 249.20 37203.70 185.98 38 123.30 114.96 39 136.04 127.97 40 251.33 243.27 41216.14 218.02 42 145.14 156.86 43 208.58 203.43 44 250.25 245.07 45235.76 250.40 46 193.19 187.83 47 211.75 223.38 48 221.15 226.04 49199.41 196.35 50 249.35 259.44 51 166.46 165.63 52 154.64 151.56 53187.36 190.37 54 256.78 260.40 55 230.59 222.39 56 208.57 224.14 57183.92 181.28 58 159.73 156.20 59 155.31 153.59 60 205.29 197.61 61204.49 198.97 62 219.21 221.45 63 122.83 114.88 64 175.13 176.48 65201.35 211.70 66 216.66 209.09 67 227.50 231.96 68 151.28 153.23 69130.10 128.40 70 175.95 173.45 71 182.38 183.21 72 201.03 195.89 73175.86 189.73 74 146.10 149.88 75 116.17 103.88 76 193.58 197.59 77291.91 296.11 78 184.93 185.49 79 145.82 141.34 80 182.73 180.78 81175.84 170.03 82 148.99 151.67 83 212.79 213.40 84 228.82 225.39 85218.44 229.26 86 169.43 173.84 87 151.43 157.96 88 217.96 218.63 89239.39 244.11 90 148.62 152.86 91 136.81 132.60 92 119.13 113.31 93121.10 119.61 94 165.31 163.34 95 111.65 132.34 96 190.25 184.44 91201.78 206.49 98 133.26 137.69 99 225.84 221.61 100 244.66 230.25 101164.72 168.10 102 150.75 146.82 103 163.51 110.41 104 196.06 198.89 105213.32 206.01 106 186.62 183.13 107 163.46 162.71 108 244.58 250.24 109231.82 231.32 110 171.94 172.27 111 201.12 209.36 112 205.41 209.00 113157.54 156.02 114 191.41 190.59 115 192.20 197.31 116 193.52 183.12 117257.83 248.49 118 178.32 171.44 119 203.64 209.32 120 210.36 230.25 121207.14 220.04 122 200.05 205.38 123 216.34 219.09 124 190.10 179.14 125293.34 272.48 126 228.57 226.02 127 111.60 174.88 128 142.80 148.94 129197.16 205.05 130 220.50 218.43 131 220.32 231.50 132 255.18 255.23

A comparative linear regression was generated for the data pointscollected in this Example. The linear fit followed the followingequation:Normal Cholesterol=−1.16+1.00 ×Serum Cholesterol,with the correlation coefficient, expressed as R², being 0.966.

EXAMPLE 6

This example demonstrates the performance of the invention in themeasurement of HDL. The dried spots and venous blood specimens from thesame one hundred Thirty-two patients in Example 5 were used to measureHDL in capillary blood it to a measured value for HDL in venous blood.The normalized HDL level in capillary blood was obtained according tothe present invention using a formula: Normalized HDL=MeasuredHDL/(A+B×(Measured Sodium/139)), where A and B were obtained aspreviously described. The following results were observed. Patient SerumHDL Normalized HDL 1 58.90 61.12 2 41.28 42.33 3 38.54 39.15 4 48.8446.19 5 61.56 54.98 6 52.68 48.79 7 47.69 45.15 8 34.69 39.49 9 57.4556.32 10 38.00 36.33 11 47.53 42.14 12 60.04 58.94 13 36.08 37.35 1446.09 48.37 15 42.22 42.82 16 34.70 38.98 17 55.76 55.79 18 21.16 24.5319 55.33 55.69 20 44.66 42.65 21 83.26 81.00 22 44.33 46.14 23 40.7140.69 24 47.24 43.98 25 49.46 47.71 26 44.37 43.30 27 50.16 48.34 2855.49 61.30 29 58.90 61.12 30 41.28 42.33 31 38.54 39.15 32 48.84 46.1933 61.56 54.98 34 52.68 48.79 35 47.69 45.15 36 34.69 39.49 37 57.4556.32 38 38.00 36.33 39 47.53 42.14 40 60.04 58.94 41 36.08 37.35 4246.09 48.37 43 42.22 42.82 44 34.70 38.98 45 55.76 55.79 46 21.16 24.5347 55.33 55.69 48 44.66 42.65 49 83.26 81.00 50 44.33 46.14 51 40.7140.69 52 47.24 43.98 53 49.46 47.71 54 44.37 43.30 55 50.16 48.34 5655.49 61.30 57 49.27 45.94 58 51.73 51.78 59 38.07 36.98 60 38.22 38.4961 43.57 45.05 62 54.16 51.46 63 38.66 34.13 64 50.14 48.65 65 57.9454.11 66 46.02 44.67 67 49.21 52.36 68 43.15 45.31 69 37.20 38.42 7049.66 50.00 71 63.00 65.28 72 79.92 79.17 73 37.12 44.57 74 59.14 60.3575 32.49 28.57 76 56.08 59.37 77 64.22 70.04 78 46.54 48.66 79 37.6837.28 80 75.41 74.70 81 44.06 44.73 82 40.65 40.88 83 93.40 91.97 8440.97 47.04 85 69.63 75.17 86 36.13 38.81 87 34.88 36.42 88 43.90 49.4089 63.29 66.41 90 49.21 49.65 91 29.54 31.27 92 49.30 49.87 93 35.8234.39 94 49.66 51.20 95 39.01 39.79 96 36.92 34.49 97 43.40 43.45 9848.70 45.97 99 42.15 41.04 100 59.09 55.11 101 49.46 47.04 102 33.3629.81 103 49.36 47.93 104 43.02 39.12 105 39.81 41.06 106 60.29 56.62107 59.84 55.33 108 84.77 82.31 109 55.20 55.72 110 54.77 56.06 11169.16 67.30 112 38.18 40.50 113 37.11 36.49 114 51.31 49.24 115 39.6942.54 116 61.17 56.56 117 29.94 30.25 118 75.50 77.62 119 56.94 57.49120 68.89 71.30 121 37.89 40.82 122 73.57 72.14 123 78.31 78.16 12448.88 47.45 125 83.96 79.26 126 95.12 92.48 127 51.44 52.50 128 38.8838.10 129 41.70 44.58 130 47.80 46.24 131 56.42 59.35 132 55.14 56.98

A comparative linear regression was generated for the data pointscollected in this Example. The linear fit followed the followingequation:Normalized HDL=2.47+0.953×Serum HDL,with the correlation coefficient, expressed as R², being greater than0.96.

EXAMPLE 7

this example demonstrates the performance of the invention in themeasurement of triglycerides (TG). The dried spots and venous bloodspecimens from the same one hundred thirty-two patients in Example 5were used to measure TG in capillary blood compare it to a measuredvalue for TG in venous blood. The normalize (TG) level in capillaryblood was obtained according to the present invention using the formula:Normalized TG=Measured TG/(A+B×(Measured Sodium/139)), where A and Bwere obtained as previously described. The following results wereobserved. Patient Serum TG Normalized TG 1 73.24 55.65 2 97.89 97.31 345.26 38.38 4 70.31 60.30 5 119.71 119.33 6 105.97 100.56 7 77.47 73.308 220.18 236.94 9 191.79 203.18 10 177.10 177.03 11 112.19 116.71 1273.24 55.65 13 97.89 97.31 14 45.26 38.38 15 70.31 60.30 16 119.71119.33 17 157.70 164.69 18 122.09 124.56 19 66.86 63.24 20 138.31 151.0821 146.08 137.36 22 95.85 97.05 23 77.27 60.69 24 85.44 82.87 25 86.2577.32 26 112.51 110.68 27 176.25 184.16 28 190.63 189.57 29 95.17 98.9230 98.52 98.76 31 102.13 97.07 32 117.77 128.91 33 123.08 125.56 34135.72 132.69 35 76.46 71.14 36 230.90 210.77 37 80.41 67.66 38 99.4385.63 39 86.87 91.07 40 125.01 120.98 41 362.90 322.04 42 132.98 118.4743 83.21 75.43 44 52.45 53.34 45 53.91 50.52 46 349.76 357.87 47 135.25139.57 48 209.20 208.33 49 374.36 386.86 50 74.90 79.81 51 395.31 399.3452 56.38 54.87 53 217.08 258.78 54 52.83 71.35 55 136.53 144.81 56115.98 118.45 57 78.41 62.45 58 70.38 65.13 59 91.00 68.59 60 180.98179.72 61 163.32 188.88 62 72.16 65.05 63 102.89 101.45 64 50.24 49.0565 184.45 195.42 66 183.07 194.25 67 65.28 65.04 68 111.40 109.43 6967.25 87.27 70 74.92 72.25 71 100.19 105.33 72 136.82 132.52 73 119.29129.90 74 119.76 119.83 75 121.90 125.90 76 75.55 80.65 77 74.44 89.0678 226.78 243.05 79 71.19 78.23 80 98.89 93.66 81 127.93 135.56 82333.65 352.31 83 97.18 91.96 84 139.77 133.20 85 73.23 72.05 86 160.00148.64 87 131.69 133.49 88 69.07 66.79 89 271.22 248.43 90 91.86 98.0091 231.14 224.76 92 153.65 171.85 93 115.95 107.16 94 263.50 257.68 9595.38 92.85 96 143.96 125.21 97 110.10 131.36 98 97.72 93.75 99 158.22151.23 100 123.80 127.26 101 279.56 271.61 102 192.26 176.02 103 59.4159.23 104 197.04 186.32 105 182.29 170.98 106 96.16 91.53 107 80.4672.56 108 65.55 68.16 109 215.37 210.92 110 186.09 191.14 111 96.4196.52 112 78.68 80.54 113 83.96 73.13 114 207.32 208.03 115 37.41 37.32116 103.17 93.38 117 193.21 210.21 118 119.46 103.27 119 67.57 58.99 120119.56 117.34 121 75.42 52.90 122 311.18 315.01 123 67.72 68.28 124127.36 129.28 125 59.82 64.57 126 85.54 83.90 127 43.24 41.49 128 85.0978.05 129 95.15 99.45 130 92.21 75.05 131 72.46 88.51 132 56.52 57.13

A comparative linear regression was generated for the data pointscollected in this Example. The linear fit followed the followingequation:Normalized TG=−2.5+1.01×Serum TG,with the coefficient, expressed as R², being 0.98.

EXAMPLE 8

This example demonstrates the performance of the invention in themeasurement of LDL. The same observations from the same one hundredthirty-two patients in Example 5, 6 and 7 were used to calculate a valuefor LDL in serum and a value for LDL in MSS according to the Friedewaldformula:Serum LDL=Serum Cholesterol−Serum HDL−Serum TG/5Normalized LDL=Normalized Cholesterol−Normalized HDL−Normalized TG/5.

The following results calculated: Patient Serum LDL Normalized LDL 1110.85 101.31 2 97.93 101.60 3 109.82 103.89 4 110.51 112.89 5 108.21107.74 6 126.07 121.49 7 49.76 54.13 8 173.19 173.53 9 78.72 77.71 10129.52 119.61 11 174.74 180.58 12 149.04 140.09 13 98.72 101.13 14115.22 115.25 15 187.28 180.56 16 146.29 158.21 17 195.20 200.00 18167.30 161.22 19 101.87 99.92 20 122.26 127.45 21 168.27 164.79 22149.27 148.28 23 100.92 85.06 24 129.40 115.93 25 92.09 88.71 26 165.02175.92 27 114.88 104.61 28 94.16 90.62 29 154.94 142.87 30 114.95 117.3931 144.71 148.13 32 152.62 164.12 33 105.78 111.48 34 105.62 106.95 35101.99 102.99 36 143.96 145.31 37 119.65 105.96 38 68.65 63.55 39 78.0275.16 40 180.50 174.23 41 110.10 109.10 42 72.00 80.58 43 124.52 118.9444 140.68 128.72 45 165.02 178.66 46 92.96 83.43 47 145.15 156.72 48133.07 131.63 49 105.59 101.08 50 177.71 184.34 51 102.56 101.25 5291.72 95.09 53 123.82 129.64 54 194.21 203.38 55 144.23 138.11 56 120.42125.06 57 120.22 122.32 58 87.42 84.13 59 107.19 106.80 60 130.18 120.0361 124.30 115.07 62 151.99 156.98 63 61.89 58.86 64 111.54 110.38 65128.43 143.14 66 150.60 143.35 67 150.93 153.10 68 84.28 81.94 69 68.9566.01 70 101.92 98.27 71 104.27 101.79 72 106.22 98.91 73 93.38 96.56 7472.72 73.88 75 63.90 56.58 76 111.92 111.11 77 160.96 155.60 78 118.95118.43 79 80.19 77.42 80 92.68 91.67 81 99.78 95.56 82 82.00 84.09 83105.58 108.07 84 133.61 128.66 85 130.44 134.49 86 87.08 90.07 87 85.8287.16 88 150.87 147.80 89 123.40 126.22 90 80.33 84.64 91 78.47 76.28 92107.81 97.16 93 65.74 66.47 94 84.06 81.90 95 53.88 67.10 96 97.42 95.6397 119.93 127.83 98 72.69 79.87 99 144.28 143.36 100 149.12 140.94 10196.03 102.76 102 101.29 102.50 103 101.09 108.85 104 109.96 117.58 105136.29 126.72 106 107.05 107.20 107 87.89 91.28 108 143.01 153.30 109135.15 134.00 110 109.68 108.74 111 117.33 123.38 112 128.59 126.45 11396.53 98.88 114 126.58 129.56 115 128.60 131.36 116 117.26 116.58 117165.65 155.24 118 89.27 80.15 119 121.23 125.97 120 129.51 146.03 121152.74 162.44 122 117.83 124.94 123 121.01 125.32 124 122.19 111.80 125190.94 178.21 126 118.95 115.83 127 108.85 110.95 128 76.17 84.41 129116.38 120.15 130 116.39 113.82 131 134.85 142.75 132 173.09 172.40

A comparative linear regression was generated for the data pointscollected in this Example. The linear fit followed the followingequation:Normalized LDL=−0.25+1.00×Serum LDL,with the correlation, expressed as R², being equal to 0.96.

It is thus seen that the invention provides a method for determining thelevel of an analyte in a specimen.

While particular embodiments to the invention have been describedherein, the invention is not limited thereto, but to the contrary shouldbe deemed defined by the full scope of the appended claims. Allreferences and prior and co-pending applications cited herein are herebyincorporated by reference in their entireties.

1. A fluid collector comprising an absorbent substrate coated with asaccharide, said substrate comprising a mat of glass fibers at leastsubstantially coated with polyvinyl alcohol, said fibers defining aplurality of pores, the pores in said mat having a pore size effectiveto at least substantially prevent lysing of red blood cells whilepermitting at least substantial separation of serum from red blood cellsvia differential wicking.
 2. A fluid collector according to claim 1, theaverage pore size defining a fluid removal rating of 1.7 micron.
 3. Afluid collector according to claim 1, said saccharide comprising xylose.4. A fluid collection device comprising the fluid collector of claim 1and a superstrate, said fluid collector being generally fixed withrespect to said superstrate, said superstrate having an aperturedefining a blood receiving opening and permitting access to said fluidcollector.
 5. A fluid collection device according to claim 4, said fluidcollector having a first end and a second end, said aperture permittingfluidic access to said first end of said collector, said superstratehaving a second aperture relatively proximal said second end of saidfluid collector.
 6. A fluid collection device comprising a pair of fluidcollectors, each in accordance with claim 1 and a single superstrate,said fluid collectors ordinarily not being in fluidic contact with oneanother and each being generally fixed with respect to said superstrate,said superstrate having a pair of apertures, each defining a bloodreceiving opening and permitting access to a respective one of saidfluid collectors.
 7. A fluid collection device according to claim 6,said superstrate comprising a second pair of apertures, each of saidfluid collectors having a first end and a second end, said bloodreceiving openings permitting respectively fluidic access to the firstend of one of said fluid collectors, said second pair of apertures eachbeing respectively relatively proximal said second end of one of saidfluid collectors thereby defining a pair of gangs.
 8. A kit comprisingthe fluid collection device of claim 4 and instructions for using thecollection device.
 9. A kit according to claim 8, said instructionsbeing integral with said device.
 10. A kit according to claim 8, saidinstructions being separate from said device.
 11. A kit comprising thefluid collection device of claim 4 and a requisition form, saidrequisition form permitting indication of the type of test to beconducted on the fluid to be collected by the device.
 12. A testaccording to claim 11, said requisition form listing a plurality of testtypes.
 13. A kit comprising the fluid collection device of claim 4 and adessicant, said dessicant being present in an amount effective toprovide a dessicating protective effect on a blood fluid specimen.
 14. Akit according to claim 13, said dessicant comprising silica.
 15. A kitaccording to claim 14, said dessicant being contained in a porous pouch.16. A kit comprising the fluid collection device of claim 4 and alancet.
 17. A kit comprising the fluid collection device of claim 4 anda barrier film pouch sized to receive said fluid collection device. 18.A kit according to claim 17, said barrier film pouch comprising alaminar structure that includes a polyester film and an aluminum foilfilm.
 19. A kit according to claim 17, said pouch comprising at leastone self-sealing device.
 20. A kit comprising: the fluid collectiondevice of claim 4; a lancet; instructions for using the kit; adessicant, said dessicant being present in an amount effective toprovide a dessicating protective effect on a blood fluid specimencollected in said device; and a barrier film pouch sized for receivingsaid fluid collection device and said dessicant.
 21. A kit according toclaim 20, further comprising a requisition form permitting indication ofthe type of test to be conducted in the fluid to be collected by thedevice.
 22. A method for collecting a specimen from a patient,comprising: providing a fluid collector, said fluid collector comprisingan absorbent substrate coated with a saccharide, said substratecomprising a mat of glass fibers at least substantially coated withpolyvinyl alcohol, said fibers defining a plurality of pores, the poresin said mat having a pore size effective to at least substantiallyprevent lysing of red blood cells while permitting at least substantialseparation of serum from red blood cells via differential wicking; andallowing said patient to bleed onto said for collector until at least apredetermined adequate amount of blood has been deposited onto saidcollector.
 23. A method according to claim 22, said fluid collectorbeing included in a fluid collection device that includes a sampleadequacy indicator.
 24. A method according to claim 23, said sampleadequacy indicator including an aperture that is spaced from the pointof introduction of fluid onto said collector.
 25. A method according toclaim 22, further comprising sending the collector to a remote locationfor testing.
 26. A method according to claim 25, comprising sealing thecollector in a barrier film pouch.
 27. A method according to claim 26,said barrier film pouch comprising a laminar structure that includes apolyester film and an aluminum foil film.
 28. A method according toclaim 26, further comprising adding a dessicant to said barrier filmpouch, said dessicant being present in an amount effective to provide adessicating protective effect on a blood fluid specimen.
 29. A methodaccording to claim 28, said dessicant comprising silica.
 30. A methodaccording to claim 25, further comprising receiving a results reportingform after sending said collector to a remote location for testing. 31.A method according to claim 22, further comprising indicating a type oftest desired on a requisition form.
 32. A method for collecting aspecimen, comprising receiving a fluid collector, said fluid collectorcomprising a mat of glass fibers at least substantially coated withpolyvinyl alcohol, said fibers defining a plurality of pores, the poresin said mat having a pore size effective to at least substantiallyprevent lysing of red blood cells while permitting at least substantialseparation of serum from red blood cells via differential wicking; andbleeding onto said collection until at least a predetermined adequateamount of blood has been deposited onto said collector.
 33. A methodaccording to claim 32, said fluid collector being included in a fluidcollection device that includes a sample adequacy indicator.
 34. Amethod according to claim 33, said sample adequacy indicator including aaperture that is spaced from the point of introduction of fluid ontosaid collector.
 35. A method according to claim 32, further comprisingsending the collector to a remote location for testing.
 36. A methodaccording to claim 35, comprising sealing the collector in a barrierfilm pouch.
 37. A method according to claim 36, said barrier film pouchcomprising a laminar structure that includes a polyester film and analuminum foil film.
 38. A method according to claim 36, furthercomprising adding a dessicant to said barrier film pouch, said dessicantsaid dessicant being present in an amount effective to provide adessicating protective effect on a blood fluid specimen.
 39. A methodaccording to claim 38, said dessicant comprising silica.
 40. A methodaccording to claim 35, further comprising receiving a results reportingform after sending said collector to a remote location for testing. 41.A method for providing a test and test results to a patent, comprisingproviding a kit, said kit comprising: the fluid collection device ofclaim 4; a lancet; a dessicant, said dessicant being present in anamount effective to provide a dessicating protective effect on a bloodfluid specimen collected in said device; and a barrier film pouch sizedfor receiving said fluid collection device and said dessicant; andresults from a previous test of the patient.